Draper catches a photon and earns a patent for its invention

A new single photon detector developed by engineers at Draper can outperform existing technologies and promises significant improvements in detection range and resolution—a boon for self-driving cars and other applications. The detector uses a silicon-germanium photodiode, has ultralow dark-counting rate and timing resolution of better than one nanosecond.

The single photon detector (SPD) is the first of its kind that can be configured in an array of multiple SPDs capable of detecting single particles of light with high timing resolution, speed and efficiency over an unparalleled wavelength range, from visible to infrared.

The breakthrough earned Draper a patent and a distinction for the team that designed the detector. The technology has the ability to significantly improve remote sensing capabilities, says Steven Spector, a principal member of Draper’s technical staff.

“A sensor needs to be very efficient at detecting light. In applications like LiDAR, you are often limited in how much laser power you can use, but you want to be able to get a lot of information from the objects in the scene. The most efficient detector you can have is one that can measure every single photon coming in to identify specific objects of interest,” Spector said.

The next generation single photon detector designed at Draper is so fast and efficient that it can absorb and detect a single particle of light, called a photon, and refresh for the next one within nanoseconds. The engineers designed the system as an array of photodiodes and coupled them with single electron bipolar avalanche transistors (SEBAT) that turn an incoming photon into a large electric current that can be detected.

“A broad range of industries and research fields will benefit from a single photon detector with these capabilities,” says Spector. Other applications include quantum communications, surveillance, bioscience, imaging and nighttime operation, he added.

The patent lists the inventors as Steven Spector, Robin Dawson, Michael Moebius and Ben Lane.

The new offering adds to Draper’s growing portfolio of autonomous systems and self-driving car capabilities. The portfolio includes the Draper APEX Gyroscope—a MEMS gyroscope that provides centimeter-level localization accuracy; Draper’s all-weather LiDAR technology, named Hemera, a detection capability designed to see through dense fog and is compatible with most LiDAR systems; and Draper’s LiDAR-on-a-Chip with MEMS beamsteering technology, which creates a three-dimensional point cloud of a car’s surroundings.